Your version may well be quite different to mine. Compare the two and see what effects are created by the lexical choice in each case.
The adjectives with negative connotations are printed in blue and the adjectives with neutral connotations in green.
Overhead, the frail sun shone on the lane decorating it with insipid colours and casting a sickly light over the withering hedgerows. Rustling in the bitter breeze, gnarled dirty-brown leaves and rotten flowers seemed to mark the arrival of an impotent summer. Although the distant landscape had almost disappeared in the murky haze, a pathetic brightness bathed the hills in a cloying halo. Muddy water trickled down from the lifeless mountains to a dessciated pool, bringing scant life to the lowlands.
Sitting in the miserable warmth of the sun, a young woman spread out a picnic. She seemed uneasy in the spot she had chosen – there was certainly no doubt that the day was melancholy and the view very bleak. Lying back with closed eyes, this lonely figure in the landscape seemed diabolical. Her face suggested she was cruel, ruthless but not brutal. As she lay there, birds swooped in the biting air-currents and the pitiless ants feasted on crumbs.